NDIS_RECEIVE_HASH_PARAMETERS structure (ntddndis.h)

Artikel
05/26/2021

The NDIS_RECEIVE_HASH_PARAMETERS structure specifies the receive hash parameters for a miniport adapter that supports receive hash calculations.

Syntax

typedef struct _NDIS_RECEIVE_HASH_PARAMETERS {
  NDIS_OBJECT_HEADER Header;
  ULONG              Flags;
  ULONG              HashInformation;
  USHORT             HashSecretKeySize;
  ULONG              HashSecretKeyOffset;
} NDIS_RECEIVE_HASH_PARAMETERS, *PNDIS_RECEIVE_HASH_PARAMETERS;

Members

Header

The NDIS_OBJECT_HEADER structure for the NDIS_RECEIVE_HASH_PARAMETERS structure. Set the Type member of the structure that Header specifies to NDIS_OBJECT_TYPE_DEFAULT, the Revision member to NDIS_RECEIVE_HASH_PARAMETERS_REVISION_1, and the Size member to NDIS_SIZEOF_RECEIVE_HASH_PARAMETERS_REVISION_1.

Flags

A USHORT value that indicates what the miniport driver should do with the hash parameters. The miniport driver can use these flags to quickly determine which parameters have changed and update the hash settings accordingly.

In a set request, the flags are defined as follows:

NDIS_RECEIVE_HASH_FLAG_ENABLE_HASH

If this flag is set, enable calculating hash values on received frames and place the calculated hash value in the NetBufferListHashValue OOB information in the NET_BUFFER_LIST structure.

If this flag is clear, disable the calculation of hash values on received frames.

If receive hash calculation is enabled, the miniport driver should set this flag; otherwise, this flag should be clear.

NDIS_RECEIVE_HASH_FLAG_HASH_INFO_UNCHANGED

The HashInformation member has not changed. The hash information includes the hash types and hash function.

If this flag is set, the HashInformation member of the NDIS_RECEIVE_HASH_PARAMETERS structure should be ignored.

If this flag is cleared, the HashInformation member contains a new value that the miniport driver must use to calculate hash values on received frames.

NDIS_RECEIVE_HASH_FLAG_HASH_KEY_UNCHANGED

The secret key and associated data members have not changed.

If this flag is set, the secret key and associated data members should be ignored.

If this flag is cleared, the secret key or associated data members have changed and miniport driver must use the new information.

In a query request, the flags are defined as follows:

HashInformation

In a set request, the hash type and hash function that the NIC should use to compute the hash values for the incoming packets.

In a query request, the hash type and hash function that the NIC is using.

Overlying drivers and NDIS can use the NDIS_RSS_HASH_INFO_FROM_TYPE_AND_FUNC macro to combine the hash type and hash function into hash information and set the HashInformation member.

Miniport drivers can use the NDIS_RSS_HASH_TYPE_FROM_HASH_INFO macro to get the hash type from HashInformation and the NDIS_RSS_HASH_FUNC_FROM_HASH_INFO macro to get the hash function.

HashSecretKeySize

The size of the secret key array of the hash function, in bytes. The size of the array is 40 bytes for NdisHashFunctionToeplitz.

HashSecretKeyOffset

The offset of the secret key array of the hash function from the beginning of the NDIS_RECEIVE_HASH_PARAMETERS structure. Use this offset to get the 320-bit (40 bytes) secret key.

In a set request, the secret key can contain any data that the overlying driver chooses.

In a query request, the secret key contains the data that the NIC is using.

Remarks

The NDIS_RECEIVE_HASH_PARAMETERS structure defines the hash parameters for the OID_GEN_RECEIVE_HASH OID.

Note Protocol drivers must disable receive hash calculations before they enable RSS. If RSS is enabled, a protocol driver disables RSS before it enables receive hash calculations. A miniport driver should fail a request to enable receive hash calculations or RSS if the other service is currently enabled.

Note The secret key is appended after the NDIS_RECEIVE_HASH_PARAMETERS structure members.

Requirements

Requirement	Value
Minimum supported client	Supported in NDIS 6.0 and later.
Header	ntddndis.h (include Ndis.h)

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